What will happen if you do NOT cut the red wire on an ESC when using a BEC? You would have power from both the ESC's built in BEC and the separate BEC going to the rx. Both powered from the same battery. I'm guessing a diode prevents backfeed into the ESC in such a case.

What negative things might happen if you did not cut the red wire? A friend of mine did this on a helicopter and nothing bad happened that he could notice. Castle creations and kontronik instruct you to clip the wire. His was a castle but it did work without clipping it.

I'm putting Jeti controller and a UBEC in a new plane which is why I was curious what the worse thing that could happen if the red wire was not cut.